Digger point and locking mechanism therefor



Sept. 23, 1958 GRUBB 2,852,874.-

DIGGER POINT AND LOCKING MECHANISM THEREFOR Filed June 15, 1954 IN V ENTOR.

ATTO]? E Y5.

United rates Patent BIGGER POINT AND LGCKING MECHANISlVI THEREFOR NorvalTownley Grnbb, Portland, Oreg., assignor, by mesne assignments, toElectric Steel Foundry Company, a corporation of Gregon Application June15, 1954, Serial No. 436,756 11 Claims. (Cl. 37142) This inventionrelates to a tooth structure and mount ing means therefor useful indigging and earth handling equipment and more particularly to a diggeror box point and locking mechanism therefor adapted for use, for example, in trenchers and like equipment.

As is well known, trenchers and similar earth moving equipment aregenerally provided with teeth or points so that the teeth can be removedfor reconditioning and replacement as they become worn or broken, etc.from use. Numerous tooth structures have been provided and many are nowin use that afford removability of the tooth from the base or nose.These known tooth structures provide a relatively stable mounting forthe tooth upon the base therefor. Such structures, however, do notprovide complete solutions to the problems that confront tooth designsfor equipment of this character.

It is accordingly, an object of this invention to provide a toothstructure and locking mechanism therefor, useful in trenchers and thelike, that will overcome a number of the shortcomings in prior artstructures of this character, some of the advantages being theelimination of unnecessary dead weight in the locking mechanism, theprovision of a locking mechanism that permits the tooth or point to bemounted upon the base quickly and easily and with a minimum of effortand the provision of a locking mechanism that positively locks andaccurately seats the point upon the base.

Another object is to provide a tooth having a central chamber thatreceives therein the nose or base member, pin means being arranged in acooperative relationship with the nose and point to position and lockthe same together. Still another object is to provide a point adaptedfor use in trenchers having a base adapted to receive the tooth thereon,the base having a transverse passage therethrough carrying acompressible pin and the point providing recesses alignable with the pinin one position of the point upon the base.

Yet another object is in the provision of a digger tooth having acentral chamber equipped with aligned recesses therein, a basereceivable wihin the chamber and having a bore therethrough enlargedcentrally and alignable with the recesses and a resilient pin carriedwithin the bore, compressible therethrough and with end portions thatsnap into the recesses to lock the base and tooth together. Additionalobjects and advantages will appear as the specification proceeds.

An embodiment in the invention is illustrated in the accompanyingdrawing, in which Figure 1 is a side view in elevation of a tooth inposition upon its base; Fig. 2 is a vertical sectional view taken on theline 2-2 of Fig. 1; Fig. 3 is a broken trans verse sectional view takenon the line 33 of Fig. 1; Fig. 4 is a broken sectional view similar tothat of Fig. 3, but showing the tooth released from the lockingmechanism; Fig. 5 is a broken sectional view similar to that of Figs. 3and 4, but showing the tooth in an intermediate position during theseating thereof upon its base; and

Fig. 6 is an enlarged cross-sectional view of a modified form of the pinpresented in Fig. 4.

In the drawing the tooth or point is designated with the numeral 10 andthe base or nose member is designated with the numeral 11. The point ortooth 10 as shown best in Figs. 1 and 2, has side walls 12 and 13, a topwall 14 and a bottom wall 15. All of the walls are rigidly securedtogether and may be formed integrally in a casting operation. The sidewalls 12 and 13 are spaced apart and define therebetween a cavity orchamber 16. The top Wall 14 is relatively fiat, while the bottom wall 15is inclined upwardly and forwardly toward the tip 17 of the tooth. Thus,the top and bottom walls of the chamber 16 converge toward the tip 17 ofthe tooth. The top wall 14 is elongated and pro vides a shroud or flange19 that extends rearwardly and over the top of the base member 11.

The spaced-apart side walls 12 and 13 of the tooth are equipped withaligned recesses or notches 20 and 21 and beveled channels 22 and 23,also .formed in the walls 12 and 13 of the tooth, communicate at theirinner ends with the recesses 20 and 21, respectively, and from therediverge outwardly and rearwardly to the rear edges of the walls 12 and13.

The base 11 has a forward end portion 24 that is adapted to be receivedwithin the cavity or chamber 16. The forward portion 24 has parallelside walls which are spaced slightly from the walls 12 and 13 of thetooth when the tooth is set upon the base, while the top wall 25 andbottom wall 26 of the nose provide a matching taper that iscomplementary with and corresponds to the taper provided between thewalls 14 and 15 of the tooth. Thus, as is clear from Fig. 1, the tooth10 is adapted to set firmly upon the forward end portion 24 of the base.i

The base 11 and more especially the forward end portion 24 thereof, isprovided with a bore or passage 27 extending transversely therethroughand which is alignable with the recesses 20 and 21 of the tooth in oneposition of the tooth upon the base. The bore 27 intermediate the endsthereof and at substantially the midpoint, is enlarged to provide thecentral enlargement 28.

To lock the tooth in position upon the base, a resilient plug or pin 29is provided which is adapted to be received within and carried withinthe bore 27 with its end portions 30 and 31 extending outwardly from thebore. The pin 29 is both resilient and compressible so that it can becompressed longitudinally to move the end portions 30 and 31 thereofsusbtantially into the bore 27. The pin, however, must have the propertyof expanding freely when compressive forces are released from the endsthereof so that the end portions of the pin can expand into the recesses20 and 21, as shown most clearly in Figs. 2 and 3. It has been foundthat molded rubber provides a suitable material for the pin 31..

Preferably, the end portions 30 and 31 of the pin have bonded theretometal sheaths that enclose the ends of the pin, or if desired, the endportions may be metal and the metal ends bonded to the rubber centralportion 32 of the pin.

In operation of the structure the tooth 10 is provided, as has beendescribed, with a chamber 16 having aligned recesses 20 and 21 inspaced-apart wall portions thereof. The base member 11 is also provided,as indicated, with a bore 27 therethrough. The pin 29 is inserted intothe bore 27 with the end portions 30 and 31 extending outwardlytherefrom. The tooth 10 is then moved toward the base 11 and the forwardend portion 24 of the base is received within the chamber 16 of thetooth, as shown in Fig. 4. i i

As the tooth 10 is pushed further rearwardly toward seating relationupon the base 11, the end portions 30 3 4 and 31 of the resilient pinengage the inclined channel operative to facilitate axial compression ofsaid pin during membersv 22- and 23 and the pin 29-iscompressed, as themountingof'said tooth upon said base. shown in Fig. 5. Free compressionof the pin is afforded 5. The structure of claim 3 in which said pin isrubber because of the central enlargement 28 of the bore 27. and the endportions thereof are enclosed by metal This: enlargement permits thecentral portion 32 of" the 5 sheaths. pin to expand diametricallywhile'the length' thereof is 6. The structure of claim 3 in which saidtooth is decreased throughthe axial compressive forces applied equippedalong the top wall thereof with a rearwardly exto. theendsvof the pin.The-minirnum point of -comtending flange that provides a shroud forprotection 'of pression is'illustrated in Fig. 5. said base.

When the tooth is-urged rearwardly andonto the 7. In a digger tooth andlocking mechanism structure basell and 'past' the point ofmaximumcompression of substantiaily as described, a tooth having an. enlargedrear the pin 29,- as shown in Fig. 5, the pinexpands and the end portionproviding a central chamber therein, at least end-portions-30'and 31thereof snap into' the recesses 20' one of the walls defining saidchamber being inclined to and 21 0f the'tooth, as shown in Figs; 2' and3. In this provide: a tapering chamber, two of the walls' of saidposition-the tooth isproperly seated upon the base-11 and chamber whichare in facing relation being provided with the-: base and' tootharefirmly'lockedtogether by th pin aligned recesses therein, the wallportions adjacent said 293 recesses being equipped with channels whichdiverge latsubstantiallynoplay is permitted-between the tooth orally andrearwardly from the recesses and toward the 10 andibase- 11 for the endportions of the passage 27 rear end portion of said chamber, a basemember having are. not enlarged and substantially engage the walls of 2.tapered forward end receivable Within said chamber and h i 29; yet theenlarged central portion 28 of the being provided'with a boretherethrough alignable with passage 27 permits free expansion of the pindiametricalsaid recesses, a compressible, resilient pin carried in saidly'when the axial length thereof is reduced. This onebore and having endportions normally extending 011tpiece locking mechanism permits readyassembly of the wardly therefrom, Said bore having an enlarged centraltooth and base and it is only necessary to push the tooth Portion PCross-Sectional eXpahsioh of said P rearwardly and onto the base 11 andin such operation during aXial compression thereof, the end Portions ofSaid thepin is first compressed and then snaps into locking p beingadaptedto Tide Within Said Channels during the position to securelyanchor the tooth upon thebase when mounting 0f Said moth p Said basewhereby the P th t th i ly d thereon, Th shroud 19, is compressedaxially between inclined Walls of said chanhi h extends. along h top 1125 of h base, h i 30 nels and thereafter expands into said'recesses tolockthe by protects thearea of thebase which is normally subtoothbasetogethel; Said P having relatively high ject'to-the greatest amountof 'wear; It also adds to the Shear stl'ellgthrigidit f. the toothmounting upon the base-by Provid. 8. The structure of claim 7 in whichsaid tooth along, i a greater b i area, the top wall thereof is equippedwith a rearwardly extend Whil i th fo i ifi ti an embodiment f ingflange that extends over said base when said tooth is the invention hasbeen set out in considerable detail, for mounted thereon purposes ofillustration, it will be apparent to those skilled' Thestructurecif'clalm 8 111 Whlch sa1d P 15 molded in the-art that numerouschanges-may be'made in 'these rubber and hasmetalhc end portionsdetailswithout departingfromthe principles and the a Structure of Characterdescflbed; a tooth" irit f-th invention; 40 and a base'member, onehaving a chamber therein d'eclaim: fined inpart by-facing walls'havingspaced-apartportions, 1. In" a structure of the characterdescribed, atooth Said h Portions each y a reCeSS h h i a a i thereinandavbasemember having v the other providing at least a portion thereofreceivable tion receivable within the cavity, the walls of said cavityWlthm sa1d chamber and havlhg a bore fherfathrough E having alignedrecesses therein and said portionreceiv- 5 b YQ l i a l ongltudlhany pable\withintthecavity havingia, bore therethmugh align; sible, res lientpin receivable'wlthin sa1d bore and having able with said" recesses; andan elongated resilient pin P portlonsiextfmdmg gutwardly h fi i theehdipori receivablewithin. said bore and having end portions .ex tionsthereof beingreceivable Within sard'recesstistolockf tending outwardlytherefrom and being receivablewitb sald'base and tooth together sa1d Pbelng an ilntegral in aidi h Said portion is Withinsaid cavity 0 memberhaving substantial resistance to'transverse shear;

said pin being longitudinally Compressible to ff move- Said bore'beingenlarged centrally to accommodate expana ment of said Portion into Saidcavity and longitudinally sion-of said pin therein during axialcompression thereofl resilient), lock Said tooth and base together. 11.In a structure of the character described, a tooth 2. The structureofclaim 1, in which said pin is an imd'a base m one hailing chambertherein defined) integral member having metallic end portions wherebyPart by facmg Walls havmg shaced'apart portlolls said said pin possessessubstantial resistance to transverse F each hilvmg a recess therem theShean other providing at least a portlon thereof receivable with- 3. Ina tooth structure and locking mechanism therein sa1d chamber and havinga bore. theirethmugh alignable for, a tooth having a central chambertherein defined in between t i lwshudmany Compressib1. partby Spacedapart side Walls, said side walls, having resil ent pin receivablewithin said bore and having end aligned-recesses therein, a base memberequipped with portions extending outwardlytherefrom, the end portionsforward end portion receivable within'said chamber and, thereofrecewable P F F Q lock said being provided with a transversely extendingbore there base tooth togeiher sflald :pm'bemg an mtegral through,alignable between said recesses. Said bore being her having substantialresistance to transverse shear, the enlarged throughout thecentralportion'thereof and anin- W i f l f adlacenfi salfi recessestegral, elongated resilient pinncarried within said bore and mg ProvldedWlth mclmed channels 'dlvergmg outwardly having end portions extendingoutwardly therefrom, said and l' f f sa1d l F Q Y PT pimbeingiaxiauycompressible to Permit movement tpress sa1d pmiaxially'when said portion18 moved into aid" forwardgendportion of said base into said'chamber andchamber" thereafterexpansible so that the end portions thereof snapReferences Cited file Of this Patem intorsaid. recesses to lock:said.tooth and base together; UNITED STATES PATENTS saidintegral pin havingsubstantial strength intransverse 1,003,663 1 Skelton Sept." 19, 1911directions to withstand shearing forces thereon; 1,434,128 Leopold anOct; 31, 1922" 4. The structurerof claim 3 whereinvsaid sideiwalls ada2,546,457 Launder et-al. a Mar. 27, 1951 jacent said. recesses areprovided with divergingchannels 2,568,075 Launder Sept; 18; 1951 i

